class MigratePublishedAt < ActiveRecord::Migration
  def self.up
    Article.transaction do
      Article.find(:all).each do |art|
        art.published_at = art.create_at
        art.save!
      end      
    end
    
    Comment.transaction do
      Comment.find(:all).each do |cot|
        cot.published_at = cot.create_at
        cot.save!
      end
    end
  end
  
  def self.down
    
  end
end